Phase conductors are polyvinyl chloride (PVC) insulated, nylon jacketed, color coded for identification purposes. Jacketed with sunlight, moisture and fungus resistant gray PVC. Southwire Type UF-B cable meets or exceeds UL Standard 83, UL Standard 493, Federal Specification A-A-59544, and requirements of the National Electrical Code. Approved for direct burial without the use of conduit.